1. Field of the Invention
The present invention relates to an image-forming photosensitive composition which is to be irradiated with light directly to print out a colored image and then heated to obtain a fixed image.
As compared with known, similar image-forming photosensitive compositions, the image-forming photosensitive composition of the present invention has a reduced fog density in the non-image part and an improved .gamma. value advantageously.
2. Description of Prior Art
It has been well known that a photosensitive composition comprising a combination of a substantially colorless dye which colors when it comes into contact with an acidic substance, used for the pressure-sensitive recording paper or the like, and organohalogen compound capable of forming a free radical by light irradiation forms a colored image by the light irradiation. This fact has been disclosed in, for example, the specifications of Japanese Patent Publications Nos. 24,188/1963, 14404/1964, 17701/1964 cations Nos. 24,188/1963, 14404/1964, 17701/1964 (corresponding to U.S. Pat. No. 3,082,086) and 204/1974 and Japanese patent application Laid-Open (Kokai) Nos. 9227/1974, 126,228/1975 and 73,133/1978. However, the known image-forming sensitive compositions disclosed in the above specifications have demerits such that the fog density is high in the nonimage part, only a low .gamma. value is available and a soft image is obtained.